Flare of the hand.
You don’t have to answer this, of course, but do you also have eczema/atopic dermatitis? Your hand looks just like mine except for the flaring. I usually get it in my feet.
No worries about asking-- that's a good question! I assume you have what doctors call "hyperlinear palms," too? I've always had bizarrely wrinkly palms, and recently I was at my dermatologist's office, and she commented on them, asking if I had eczema or atopic dermatitis. So, I recently learned that hyperlinear palms are highly associated with those conditions.
But-- I have never had either condition. I am prone to dry skin, but that's about the worst of it. I'll keep my fingers crossed it stays that way.